Valgus extension overload syndrome
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Valgus extension overload syndrome, also known as pitcher's elbow, refers to a constellation of symptoms and pathologies commonly seen in overhead throwing athletes secondary to high repetitive tensile, shear and compressive forces generated by the overhead throwing motion.
The syndrome may correspond to one or a combination of injuries to the following structures:
- medial elbow stabilizers, including ulnar collateral ligament (UCL)
- radiocapitellar joint
- ulnohumeral joint
"Valgus extension overload syndrome" refers to the clinical syndrome which may be seen in adolescent or skeletally-mature athletes. Posteromedial elbow impingement is a specific injury pattern which may be seen as a component of valgus extension overload syndrome. Specifically, impingement may occur between the olecranon and olecranon fossa due to high shear forces in the posterior elbow compartment 4. The lesion may be located posteromedially, particularly if there is co-occurring UCL injury 5.
Mostly overhead throwing young athletes such as baseball players or javelin throwers.
The typical history is an athlete with posterior elbow pain at ball release. Pain is typically reported in the posteromedial elbow at full extension or during the acceleration or deceleration phases of overhead throwing. Restriction in full extension is common in throwing athletes in their dominant elbow, however, this finding can be more pronounced in this entity.
On physical examination, focal tenderness to palpation over posteromedial elbow join and crepitus are common.
Symptoms can be reproduced by placing valgus stress on the elbow at 20 to 30 degrees of flexion while forcing the elbow into terminal extension.
Extreme tensile stress forces applied to the anterior band of the ulnar collateral ligament during forced extension due to high valgus torque. This can injure ulnar collateral ligament either in the acute setting or chronically due to microtrauma.
Other excessive forces during pitch are high shear stresses in posterior compartment causing cartilage injury of the olecranon and compressive forces radiocapitellar joint with resultant osteonecrosis, particularly in skeletally immature athletes.
Imaging manifestation varies and can occur in isolation or in combination; these are as follows:
- medial elbow injuries:
- ulnar collateral ligament insufficiency
- common flexor-pronator mass (muscle or tendon) injury
- medial epicondyle epiphysitis
- ulnar neuritis
- lateral elbow injuries:
- Panner disease
- capitellar OCD
- posterior elbow injuries
On x-ray, chronic changes can be detected, e.g. osteophyte formation in the posteromedial olecranon fossa, loose bodies, capitellum osteochondral defects, calcium deposits or ossification of the ulnar collateral ligament.
MRI is the modality of choice for imaging assessment of these patients. A complete UCL tear is diagnosed by ligament discontinuity and abnormal fiber laxity. Partial thickness tears of UCL most commonly occur mid-substance and characterized by periligamentous edema, varying degrees of fiber discontinuity and increased signal intensity on fluid-sensitive images traversing the ligament fibers.
Fluid or contrast material insinuating below the ligament along the margin of the bone at the sublime tubercle known as the "T sign" can be observed due to partial avulsion of the UCL and periosteal stripping.
Thickening and T2 hyperintensity of ulnar nerve indicates ulnar neuropathy and neuritis.
Posterior compartment chondromalacia and chondral fragment with free articular osteochondral fragments.
Radiocapitellar kissing contusion, fracture or in younger patients osteochondral dessicans lesions.
Treatment and prognosis
Initially, non-invasive treatments such as NSAIDs, activity modification, steroid injections, and rehabilitation are attempted. Complete tears and failed conservative treatments after 3 months, particularly in highly active athletes, may indicate surgical UCL reconstruction with graft, known as "Tommy John surgery".